Documentation

The map of tile kinds in a place (and generally anywhere in a cave).
The map is sparse. The default tile that eventually fills the empty spaces
is specified in the cave kind specification with cdefTile.

For CAlternate tiling, require the place be comprised
of an even number of whole corners, with exactly one square
overlap between consecutive coners and no trimming.
For other tiling methods, check that the area is large enough for tiling
the corner twice in each direction, with a possible one row/column overlap.